The invention relates to electrical circuit arrangements and more specifically to frequency synthesizers for generating electrical signals at selectively different frequencies.
Frequency synthesizer circuits are known comprising a number of cascaded stages each of which for example synthesizes the value of one digit in the final output frequency. Such stages may be responsive to a reference frequency and may include means for multiplying the reference frequency to produce a frequency which is then processed to produce the output of that stage. A problem with such synthesizers is to avoid multiplication of noise within each stage.
An object of the invention is to provide an improved frequency synthesizer stage.
Another object of the invention is to provide a frequency synthesizer stage which has an improved signal to noise ratio.